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Traffic and Status of Network Interfaces Using 32-Bit Counters

Distribution: official part of Check_MK
License: GPL
Supported Agents: SNMP

This check monitors the operational status, link speed, traffic, packet counts, discards and errors of network interfaces by using the information provided by the standard SNMP MIB .1.3.6.1.2.1.2.2 (IF-MIB::ifTable). This MIB is usually supported by all SNMP devices, such as routers, switches, firewalls and even operating systems such as Windows and Linux.

Depending on the check parameters, this check can go WARN or CRIT when the port status changes (i.e. is down), when the link speed changes (e.g. a port expected to be set to 1 GBit/s operates only at 100 MBit/s), when the absolute or procentual traffic of a port exceeds certain levels or if the rate of errors or discards exceeds configurable limits.

This check supports averaging the in- and outgoing traffic over a configurable time range by using an exponentially weighted moving average - just as Linux does for the CPU load averages. The averaging can be configured on a per-host and per-interface base. Interfaces with averaging turned on yield two additional performance values: the averaged in- and outgoing traffic in bytes. If you have configured traffic levels, then those levels are applied to the averaged values.

Please note: if your devices supports SNMP v2c, you should rather add them to bulkwalk_hosts and use the check if64. This check is almost identical to if, but supports 64-bit counters and ifAlias.

Item

There are three allowed ways to specify an interface: its index ifIndex, its description ifDescr and its alias, which is the same as the description for this check.

Discovery

One service is created for each interface that fulfills configurable conditions (rule "Network interface and switch port discovery"). By default, these are interfaces which are currently found up and are of type 6, 32, 62, 117, 127, 128, 129, 180, 181, 182, 205 or 229.

Grouping: In some situations, you do not want to monitor a single interface but a group of interfaces that together form a pool. This check supports such pools by defining groups. The data of all members is accumulated and put together in a single grouped interface service.